I'm sorry to hear of your husband's Alzheimer's troubles. I am glad for both your sakes that you have a power of attorney in place, though. That was good planning.
It is common for people to sign and put "POA" after their signature, but that is not really the correct way to do it. The best practice is to sign your own signature followed by "attorney-in-fact for (insert husband's name)".
The foregoing is not intended as legal advice, but solely as general information. No attorney/client relationship exists between the poster and the answering attorney.
Just sign his name, then insert "Atorney-in-Fact" or "AIF" followed by your name.
Evan A. Nielsen is licensed to practice law in California and handles federal tax matters throughout the U.S. The information provided here is for educational purposes only and is not intended as legal advice for a particular matter. This response does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult an attorney.